"As the inmate's non-visibility was prolonged, the cell was accessed, which was found empty, so an immediate corresponding alert was emitted for the probable escape of the mentioned prisoner," Mexico's National Security Commission said in a statement Sunday.

The entrance of the tunnel measured about 20-by-20 inches and the tunnel itself was about 5 feet deep. PVC piping, likely used for ventilation and lighting, were found throughout the tunnel. A motorcycle was also found inside, apparently used to dig and to transport materials for the tunnel, according to National Security Commissioner Monte Alejandro Rubido, who visited the prison.

Mexican security forces have launched a manhunt for Guzman in the area and the highways of surrounding states. Operations at the nearby Toluca airport, about 17 miles away, have been suspended.

Guzmán was the head of the Sinaloa Cartel and was estimated to be worth about $1 billion.

El Chapo -- meaning "The Short One" or "Shorty" -- so dubbed because of his 5-foot-6-inch frame, was captured in Guatemala in 1993 and then extradited to Mexico to face murder and drug trafficking charges. He escaped from prison in 2001 by bribing prison guards and was re-captured in February 2014.